The testing of cotton fiber physical properties is practiced in the cotton industry for the purpose of evaluation in acceptance testing of cotton. One characteristic which is often tested in cotton fibers is micronaire. In micronaire testing, the air flow resistance of a compressed plug of cotton fibers placed in a closed flow chamber is determined by measuring air flow rate through the plug at a fixed pressure. In effect, the micronaire property is indicative of the fineness of the fiber.
In conventional micronaire measurement systems, a sample of cotton fiber is randomly selected from a cotton lot and weighed. The weighed sample is then transferred to a compression chamber which consists of a cylinder having a plunger for compressing the sample to a fixed volume. The sample is compressed to the predetermined volume. Air is then forced from one end of the chamber to the other through the compressed fiber plug, and the air flow rate is measured to permit calculation of a micronaire value.
In conventional systems, the operator first places a selected sample on the scale for weight determination, and then transfers the sample into a test chamber. Because the conventional test chamber compresses the plug to a constant volume, a determination of the micronaire value requires regression analysis in the calculation software to account for different test plug densities based on the variation in weight of samples selected. Indeed, in order for the testing to occur on a sample of acceptable density, the system must operate upon samples within a relatively restricted weight range because of the fact that each plug is compressed to the same volume.
With the advent of this invention, significant manipulative steps by the operator may be eliminated. Moreover, the test chamber is designed in such a way that each sample is actually tested at a constant density, the test plug when compressed having a variable volume determined by the weight of the sample selected. Both the weighing step and the air flow test are carried out in the same test chamber, and the equipment automatically ejects the fiber from the chamber at the conclusion of the test.